1. Field of the Invention
The present invention relates to a spin cleaning and drying apparatus and a spin cleaning and drying method and, more particularly, to a spin cleaning and drying apparatus which is installed in a CMP (chemical mechanical polishing) system and the like and performs the spin cleaning and drying of a substrate, such as a wafer, by single-wafer processing and a spin cleaning and drying method.
2. Description of the Related Art
In order to achieve miniaturization, semiconductor devices, electronic parts and the like are formed by being multilayer interconnected on a wafer (substrate) made of materials such as silicon. On that occasion, each time an interconnection of each layer is formed, planarization processing is performed and an interconnection of the next layer is formed on the flat surface.
In the planarization of a wafer (substrate), it has become a general practice to use a CMP (chemical mechanical polishing) system. A cleaning liquid is supplied while this wafer subjected to planarization process is being spun on a spin cleaning and drying apparatus provided in the CMP system, and finally pure water is supplied, whereby the cleaning step is completed. Furthermore, the drying step in which the pure water is discharged to the outside by spinning is carried out.
However, water drops remain in the center part of the wafer by drying which is carried out only by spinning and hence drying is insufficient also in parts other than the center part, with the result that water marks are formed in these parts. If water marks are formed, the quality of fine interconnection layers formed on the wafer deteriorates and particles occur.
In order to solve these problems in the wafer drying step, there have been proposed spin cleaning and drying apparatus in which an atmosphere cutoff plate which cuts off the outside air in an upper opening of a cup enclosing a spin chuck of the spin cleaning and drying apparatus is provided near a wafer, and in which a pure water supply port and a gas injection port which injects a drying aid gas are provided in the center part of the atmosphere cutoff plate. (Refer to the Japanese Patent Application Laid Open No. 11-330039, for example.)